There’s a reason Doris Day was, for so long, one of Hollywood’s most popular actresses: she was really, really good at her job. And let’s face it, her job wasn’t easy. Countless would-be stars would sell their souls for just one or two of the many talents that Day brought to the screen with seeming ease: the marvelous singing voice (she has a Lifetime Grammy); the comedic timing; the perky personality that, thankfully, rarely felt cloying or saccharine; the formidable dramatic chops.

In movies like Calamity Jane, Pillow Talk, Lucky Me — and in tougher-minded fare, like Love Me or Leave Mewith James Cagney — Day not only held her own with other stars: she often brought out the best in her peers. Whether in comedies (Rock Hudson) or thrillers (James Stewart in Hitchcock’s The Man Who Knew Too Much), she hit her marks, hit all the right notes, and made it look like fun. How many stars, of any era, can say the same?

Doris Day famously left the movies behind in 1968, when she was in her mid-40s, and effectively retired from acting in the mid-1970s after a successful stint on television. Over the course of her surprisingly short career she starred in dozens of films, and for years –even long after she stopped acting — she was the number one female box-office star of all time.

For the past several decades Day has led a quiet but active life in Monterey County, Calif., most notably as the founder of the celebrated Doris Day Animal Foundation — a nonprofit with, as the DDAF website notes, “a straightforward mission: to help animals and the people who love them.”

Here, in celebration of Ms. Day’s 90th birthday — she was born Doris Kappelhoff on April 3, 1924, in Cincinnati — LIFE.com offers a series of photos, none of which ran in LIFE, from the late 1940s and early 1950s, when the Ohio native with the winning smile and the gorgeous voice had Hollywood in the palm of her hand.
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